In a 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE)/Long Term Evolution-Advanced (LTE-A) system, for a downlink multiple access mode, an orthogonal frequency division multiplexing (OFDM) mode is usually used. That is, different users use different time and frequency resources, to ensure that no mutual interference occurs in signal reception of the users, but a transmission rate is relatively low. At present, for pairing in a single stream or at a single layer, two technologies, namely, non-orthogonal multiple access (NOMA) and semi-orthogonal multiple access (SOMA), are mainly used to dynamically allocate a power to a user, so as to implement interference-free high-speed transmission between users and improve a system throughput. For the NOMA, a single resource is allocated to multiple users, transmission signals of the multiple users are superposed in a time/frequency domain, and different powers are then allocated to different users to ensure accurate reception on a user side. For the SOMA, an existing modulation scheme or a Gray encode property of a constellation diagram is further used based on the NOMA, so that receivers of users use a simple reception algorithm, to implement superposition transmission between the users, thereby improving system performance.
In an application of user pairing at a plurality of layers, UE in a cell in an existing LTE system generally has a plurality of transmission modes (for example, codebook-based spatial multiplexing and non-codebook-based spatial multiplexing). During non-orthogonal or semi-orthogonal transmission between UEs that use a same transmission mode or different transmission modes, the UEs obtain power pairing information or layer pairing information in different manners. The power pairing information may be notified to the UEs by using high layer signaling or physical layer signaling or in another non-explicit manner.
A relatively large quantity of bits are needed to notify the power pairing information; overheads are relatively high. In addition, when different powers are configured on different subbands, more signaling needs to be consumed; consequently, signaling overheads of a system are increased to some extent, and a system gain is reduced.